Provoked by research on the importance of good kindergarten teachers, Greg Mankiw asks about the role of parents. The author of the kindergarten paper replies:
The best evidence I've seen on the long term impacts of parents is this quasi-experimental paper by Bruce Sacerdote published in the QJE. It shows that parental characteristics explain about three times more of the variation in adult outcomes than [kindergarten] classes, consistent with your intuition.
Leonhardt also answers:
As more and more education data is collected and more research is done both of which are happening, fortunately we may discover the impact of a good teacher is not as large as some economists now believe. Instead, we may realize that teachers matter, perhaps greatly, but that some of the gains we’re now attributing to them should in fact be attributed to other forces.
As it is, Raj Chetty, one of the economists who did the kindergarten study, notes that the effect that teachers have on their students may be significant, but it’s also small relative to all of the other forces affecting earnings. “A better class leads to higher average earnings, but there’s lots of variation around the mean,” he e-mailed me. “A lot of other things matter.”